The present specification relates generally to the field of displays. More specifically, the specification relates to virtual displays.
Virtual displays can provide information that is viewable in virtual space for a user of equipment, such as robotic equipment, remote vehicles, unmanned vehicle systems (UVSs), aircraft, ships, boats, naval craft, medical equipment, training simulators, entertainment systems, military equipment, land vehicles, etc. The information can include equipment parameters, location information, video information, remote views, etc.
Virtual displays can utilize Head Mounted Displays (HMDs) (e.g., helmet mounted displays and head worn displays) to provide images to an operator or user (e.g., a pilot in a cockpit). In aircraft applications, HMDs generally include visors, combiners, optical projection elements, an image source, and a head orientation sensor. The image source provides an image which is projected to a combiner to provide a collimated image to the pilot. The image can include enhanced vision images, targeting data, flight instrument data, synthetic vision images, head up display (HUD) data, etc.
Conventional HMDs, such as those used on modern fighters, use a complex head orientation sensor to coordinate the image provided to the pilot with respect to the view within and outside the cockpit. However, complex orientation sensors are expensive, tolerance limited, bulky, require calibration, and can be inaccurate.
Video games, computers, and entertainment systems have used cameras to track body position and body movement. The body position and body movement are used to move characters in the game environment, and/or to provide hands free computing, three dimensional modeling, virtual reality, and computer aided design. In one application, Free Track software available under the GNU General Public License can be used with inexpensive off-body cameras and fixed light patterns on the head to track head movements using a four point pose estimation algorithm or a three point geometric algorithm. In another application, the Vuzix® augmented reality system uses a camera mounted on eyewear to provide an augmented reality display.
Thus, there is a need for a low cost, lightweight head orientation sensing system for virtual display. There is also a need for a head orientation sensing method which can be used with an HMD and does not require a complex orientation sensor. There is further a need for a head orientation sensor system and method that can be easily integrated in the design of a virtual display without requiring extra display space. There is further a need for a virtual display having a lower cost. There is also a need for a virtual display system and method that is optimized for use in a cockpit environment.